Refrigerating apparatus



July 21, 1936. PHILIPP 2,048,025

REFRIGERATING APPARATUS I Filed May 9; 1952 INVENTOR. Lib Pam; I 4'.P/l/L/PP A TTORNEY.

atented July 21, 1936 Kelvinator Corporation, Detroit,

poration of Michigan Application May 9, 1

8 Claims.

cant is pumped to other parts of the system where it is not needed andwhere it is likely to affect the efiiciency of the system. Thislubricant is usually returned to the lubricant reservoir along with thevaporized refrigerant by the action of the compressor by entrainementand/ or by gravity. One form of special oil returning evaporator whichmay be used is as disclosed in Patent No. 1,719,024 issued July 2, 192to John R. Replogle. Such systems are usually intermittently operatedand during the off phase of the refrigerating cycle the pressure in thelow side builds up. In systems of this type, which are provided with arefrigerant which is miscible with the lubricant, it has been found byexperience that when the lubricant is placed in the low pressure side ofthe system, any sudden reduction of the pressure on the body of thelubricant will cause considerable foaming to take place. In suchsystems, which are in open communication with the low side of thesystem, to provide for the return of the lubricating fluid to thereservoir, it 35 has been found that a large part of the lubricant whichforms a portion of the foam is drawn into the compressor whence it isdischarged into other parts of the system. Under these conditions, anabnormal amount of lubricant is being pumped to other parts of thesystem and the return there of, as aforesaid, is less than the amount sopumped to other parts of the system. Accordingly, the compressor wouldsoon be without lubricant and the efliciency of the system would bedecreased.

' By my invention, I. obviate the above difiiculties by providing anarrangement which prevents the sudden reduction of pressure on the bodyof the lubricant.

Another object of my invention is to provide for the return of thelubricant from thecooling element through 'a passage which is arrangedto prevent the return flow of fluid therethrough, and also to arrangefor reducing the pressure of the refrigerant vapor on the body oflubricant Mick, a cor- 932, Serial No. 610,021

gradually by withdrawing the vapor through a restricted orifice orvalve.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompany- 5ing drawing, wherein a preferred form of the present invention isclearly shown.

In the drawing:

The figure in the drawing is a diagrammatic representation of arefrigerating system embody- 1o ing features of my invention and showingan enlarged full sized view in cross section of the compressor.

Referring to thedrawing, numeral 20 designates a condensing element andthe numeral 22 designates a cooling element or evaporator of the floodedtype, in which a substantially constant level of liquid refrigerant ismaintained by'means of a float valve mechanism (not shown). Thecondensing element comprises in general a compressor 26 which may beoperated by any suitable means, such, for example, as an electric' motor(not shown), and a condenser 26. Evaporated refrigerant is withdrawnfrom the evaporator through a vapor conduit 27. The evaporatedrefrigerant thus withdrawn is compressed by the compressor, as ishereinafter more fully described. The compressed refrigerant isdischarged into a conduit 29 through which it passes to the condenser 26wherein it is con- 30 densed and from which it passes to a liquidrefrigerant receiver 3i. Liquid refrigerant is supplied to theevaporator from the receiver through a liquid supply conduit 33.

The compressor 2 comprises in general an outer casing 59, which includesa crank case portion 52 adapted to contain a quantity of lubricatingoil, the level of which I have indicated at 56, and a cylinder blockportion 55. The compressor also includes a head portion 51 and a valveplate 0 58 clamped between the head portion and the cylinder block byscrews 60. Within the cylinder block there is provided .a compressionchamber 62 in which is disposed for reciprocation a piston 63' which, inturn, is connected to a pitman 66 actuated by an eccentric portion 65 ofthe compressor shaft. The compressor shaft is journaled in suitablebearings (not shown) carried by casing 50. During the operation of thecompressor the pitman 6t, eccentric 65 and an oil thrower 67, which issecured to the pitman, are adapted to dip into the body of thelubricating oil 54 and throw oil for lubricating various moving parts ofthe compressor.

Surrounding a portion of the-cylinder block is an intake chamber lformed by a portion of the outer wall of the cylinder block, designated1|, and a laterally extending wall 52 which is joined to the cylinderblock wall. This intake chamber is in communication with the vaporconduit 21. The evaporated refrigerant which is withdrawn through thevapor conduit 21 from the evaporator 22 passes through the intakechamber 10 and opening 14 provided in the valve plate 58, and into arecessed chamber 15 provided, in the head portion 51, whence it passesthrough ,a second opening 16 provided in valve plate 51, and into thecompression chamber 62 under the control of a suction check valve 18.The refrigerant is compressed within the chamber 62 whence it isdischarged therefrom through a discharge valve 18 into a recessedchamber 19 provided in the head portion, and a passage 80 which is alsoprovided in the head portion and which is in communication with theconduit 29 which leads temperature in the evaporator. Any suitable"pressure responsive control mechanism may be provided for connecting anddisconnecting the motor which "drives the compressor to and from theelectric power mains.

During operation of the compressor, some of the lubricating allcontained in the crank case portion 52 of compressor '24 is carried toother parts of the system, due to the pumping of oil by thecompressor-24. When this occurs, the level of lubricating oil within thecrank case portion 52 gradually diminishes and the lubricating oil whichis pumped to other parts of the system, for example, to the evaporator22, has a tendency to afiect the efliciency of the-system, Under theseconditions, it is necessaryto return the oil from the evaporator to thereservoir provided in the crank case of the compressor. This oil is: re-

turned as aforesaid through conduit 21 and any oil entrained with thevapor will be separated therefrom when coming in contact with the wallsof the chamber 10, and alsodue to the greatly reof chamber 10.

In theabove described system, I prefer to use a refrigerant which ismiscible with the body of oil, which refrigerant may, be, for example,CClaFa, In systems of such type in which it is desired to use arefrigerant which is miscible with refrigerant in the crank case, theamount de-' pending upon the pressure therein and the length' the bodyof the lubricating oil, it has been found, as previously stated herein,that any sudden reduction of pressure on the body of lubricant willcause considerable foaming. This is due to the fact that the oil absorbsa portion of the on the body of the lubricating oil gradually so as toprevent foaming within the crank case 52. As previously stated, thispressure on the body of lubricant is the result of pressure which buildsup in the low pressure side of the system during the off phase of therefrigerant cycle of the system. By low pressure side of the system ismeant the evaporator 22 and the low pressure portion of the compressor,which includes the crankcase 52 in which the body of lubricating oil isstored. 1 By high pressure of the system is meant between the dischargevalve 18 of the compressor and up to and including the point where theliquid refrigerant enters the evaporator 22. The building up ofpressures in the low pressure side of 1 the system during off phasecauses the pressure to build up in the crank case 52 of the body oflubricating oil 54, for the reason, that it is necessary to establishcommunication between the suction chamber 10 and the crank case portion2 v 52 in order to return the oil which has previously been pumped toother parts of the system to its reservoir; In view of the fact that therefrigerant is miscible with the oil, a. portion of the re- {frigerantvapor becomes absorbed in the oil 9 which is returned to the crank case52. In order to provide for returning the oil to the crank case portion52 from suction chamber 10, I have provided a conduit 90, which is inopen communication on its upper end with bottom wall of the suctionchamber 10, and at its discharge, or lower end 9!, I have provided avalve mechanism 92 which permits the flow of oil into the reservoir butprevents the return of any fluid through the conduit 90. By thisarrangement I may provide 3 a valve of suflicient size to return the oilto the crank case 52 without the possibility of clogging. In order towithdraw the refrigerant vapor which accumulates within the crank caseportion 52, I have provided a conduit 94 which is carried by a laterallyextending wall portion 95 of cylinderblock 56 and a horizontal wallportion 96 of the casing 50. The upper end 91 of conduit 94 isin opencommunication with the suction chamber 10 and is disposed suiiicientlyhigh-enough in the chamber so that it would be unlikely to receiveoilreturning through the vapor conduit 21 into the suction chamber 10.On the lower end of the conduit 94, which projects downwardly within thecrank case portion 52, there is pro- 50 vided a valve or restrictedorifice Hill. This restricted orifice is provided for limiting theamount of refrigerant vapor which is withdrawn fromthe crank caseportion into the compression chamber by the action of the piston 63.Thus,

this restricted orifice serves to provide a means for gradually reducingthe pressure within the crankcase portion 52. The restricted orifice I00also limits .the amount of refrigerant vapor en tering into the crankcase during the on phase of 60 the system. Consequently, the pumping ofoil by the compressor to other parts of the system is reduced to anegligible amount since the possibility of foaming within the crank caseportion 52 occuring in response to sudden reduction of 5 pressurestherein is substantially or entirely obviated by such an arrangement.

Although only a preferred form of the invem tion has been illustrated,and that form described in detail. it W be pparent to those skilled in 9the art that various modifications may be made therein without departingfrom thespirit of the invention or from the scope of the appendedclaims.

What is claimed is as follows:

1. A refrigerating apparatus for circulating a volatile refrigerantcomprising in combination a casing, a compressor disposed in saidcasing, said casing being adapted to provide a reservoir for lubricatingfluid for lubricating moving elements of the compressor, saidrefrigerant being miscible conducting evaporated refrigerant from theevaporator to the compressor to be compressed and for conductinglubricating fluid from the evaporator delivered thereto by the action ofthe compressor to the suction side of the compressor, fluid conduitmeans for delivering the lubricant from the suction side of thecompressor to said reservoir and for preventing the return of lubricantand refrigerant therethrough, means in communication with the suctionside of the compressor for restricting the amount of refrigerant vaporentering said reservoir, said vapor being adapted to create a pressureon the body of lubricating fluid, said last named means also serving topermit the reduction of pressure on said-oil at a rate below that whichwould cause the foaming of said oil.

2. A refrigerating system of the type wherein a volatile refrigerant andoil are circulated comprising a high pressure portion and a low pressureportion having a reservoir for oil and a second reservoir containing aquantity of liquid refrigerant, an oil conducting conduit having itsinlet end associated with the low pressure portion above the level ofliquid refrigerant and its outlet end associated with said reservoir,and a valve below the level of oil in said reservoir for controlling thepassage of oil through said conduit.

3. A refrigerating system of the type wherein a volatile refrigerant andoil are circulated comprising a high pressure portion and a low pressureportion, said low pressure portion having a reservoir containing aquantity of oil and a second reservoir containing a quantity of liquidrefrigerant, and an oil conducting conduit having its inlet end.associated with said low pressure portion above the level of liquidrefrigerant and its outlet end associated with said reservoir below thelevel of oil therein.

4. A refrigerating system of the type wherein a volatilerefrigerant andoil are circulated, comprising a high pressure portion, a low pressureportion having a reservoir containing a quantity of oil and a secondreservoir containing a quantity of liquid refrigerant, and an oilconducting conduit having its inlet end associated with said systemabove the level of liquid refrigerant for receiving oil and its outletend associated with said reservoir below the level of oil therein.

5. A refrigerating system of the type wherein a volatile refrigerant andoil are circulated, comprising a high pressure portion, a low pressureportion having a reservoir containing a quantity of oil and a secondreservoir containing a quantity of liquid refrigerant, an oil conductingconduit having its inlet end associated with said system above the levelof liquid refrigerant for receiving oil and its outlet end associatedwith said reservoir below the level of ,oil therein, and means forcontrolling the passage of oil through said conduit.

6. A refrigerating system of the type wherein a volatile refrigerant andoil are circulated, comprising a high pressure portion and a lowpressure portion having a reservoir containing a quantity of oil, an oilconducting conduit having its inlet end associated with said system forreceiving oil and its outlet end associated with said reservoir belowthe level of oil therein, said refrigerant being miscible in said oiland being adapted to create a pressure thereon whereby a portion of saidrefrigerant becomes absorbed in the oil, and means for reducing thepressure on said oil at a rate below that which would cause the foamingof said oil by the reduction of pressure thereon.

7. A refrigerating system of the type wherein a volatile refrigerant andoil are circulated; comprising a high pressure portion and a lowpressure portion having a reservoir containing a quantity of oil, an oilconducting conduit having its inlet end associated with said system forreceiving. oil and its outlet end associated with said reservoir belowthe level of oil therein, said refrigerant being miscible in said oiland being adapted to create a pressure thereon whereby a portion of saidrefrigerant becomes absorbed in the oil, a valve for controlling theflow of oil through said conduit, and means for reducing the pressure onsaid oil at a rate below that which would cause the foaming of said oilby the reduction of pressure thereon.

8. A refrigerating system of the type wherein a volatile refrigerant andoil are circulated, comprising a high pressure portion and a lowpressure portion having a reservoir containing a quantity of oil, an oilconducting conduit having its inlet end associated with said system forreceiving oil and its outlet end associated with said reservoir, saidrefrigerant being miscible in said oil and being adapted to create apressure thereon whereby a portion of said refrigerant becomes absorbedin the oil, means for reducing the pressure on said oil at a rate belowthat which would cause the foaming of said oil by the reduction ofpressure thereon, said means including additional conduit means having arestricted orifice, and a valve for controlling the'fiow of oil throughsaid oil conducting conduit.

LAWRENCE A. PHILIPP.

